Most everyone is familiar with their 5 senses: tactile (touch), vision, hearing, smell/olfactory, and taste. However, there are 2 other sensory systems that are often discussed in occupational therapy which are the vestibular and proprioceptive systems. Although all of our sensory systems work together and are all a necessary part of efficient sensory processing, these “other two” senses are often integral parts of our therapy sessions and subsequent home programs.
Lets back up for a moment and discuss a quick overview of sensory integration. Sensory integration is the ability to take in information from our body and the environment so that you can use that body effectively and efficiently within the environment. When you bring your child to occupational therapy there is some break down in function within the environment. Whether it be difficulty with handwriting, transitions, meltdowns, difficulty in school or any other example, somewhere in this exchange of information there has been a breakdown. A child may be avoiding or seeking input, they may be registering input as a threat when it isn’t (over-responsive) or not noticing input (under-responsive). Our bodies are designed to want to be in an organized state. The behaviors or symptoms children with sensory processing dysfunction exhibit are ways of avoiding disorganization and/or gaining organization. To make a change in the system we need targeted interventions that are done with intensity, consistency, and frequency. Sensory integration therapy literally works to lay down new neuro pathways in the brain and organize already existing pathways.
The vestibular system is arguably the most important of all our sensory systems, it is our gravity sense. It is the first system to develop in-utero and the only one to develop fully in utero. All of the other sensory systems get stem cells from the vestibular system. Your vestibular system has primary receptors in your inner ears called semicircular canals and otholiths (utricle and saccule). Receptors are where the sensory input enters our bodies/brains from, it is how we receive the input. Both of these receptors detect movement of your head and body in space. Your semicircular canals detect fast, angular, changing and rotary input. When a therapist spins your child and reports on a “post rotary nystagmus” or “PRN”, they are talking about the functioning of their vestibular system and more specifically their semicircular canals. Your otholiths detect linear movement as well as slow, positional movement; they are responsible for posture. Think about a baby engaging in tummy time. The baby lifts his/her head and activates all the muscles along the back while the vestibular system is also fired from the movement of the head. Then the baby’s muscles fatigue and they bring their head back down. This early movement pattern is a part of the beginning of the connection between our vestibular system and our posture. It translates all the way up to the child who sits with their head resting in their hands versus upright.
What does this mean in context of our daily life? The vestibular system tells us if we are moving or not, and how fast we are moving. It also tells us in which direction we are moving. Are we upright, upside down, or at a tilt? It tells us whether objects are moving or still in relation to our body. The system helps us feel safe and comfortable as we move. Here are a few examples. Have you ever had the experience of sitting beside a car at a traffic light and when that car starts to move you feel as though you are moving? You have tripped off your vestibular system. Another example, when you slip on ice your hands move out to protect your fall before you even have time think about the fact that you are falling. Your vestibular system detects the movement and starts the communication to generate a motor response. Your vestibular system works constantly in conjunction with the other sensory systems. However, your vestibular system is what keeps you upright, so you are constantly using it to navigate your body against gravity. This is why when a therapist detects some dysfunction within the vestibular system we start working there. Because our vestibular system is so primal it can elicit very strong emotions and this has to be considered in therapy sessions and home programs.
Some children may be over responsive to vestibular input and exhibit some of the following:
-Overreact, negatively and emotionally, to ordinary movement
-Dislike physical activities (running, biking, sledding, or dancing)
-Avoid playground equipment (swings, slides, jungle gyms, and merry go rounds)
-Be overly cautious and slow moving
-Not like to have head upside down (for example, when washing hair)
– Easily carsick or seasick; very sensitive to escalators and elevators
Other children may be under responsive to vestibular input and exhibit some of the following:
-Not notice sensation of falling or being off balance, not protect self well
-Not notice or object to being moved
-Swing for a long time without dizziness
Some children may seek extra vestibular input and exhibit the following:
-Crave intense, fast, spinning movement (spin themselves or constantly run in circles, spin in office chairs, jump on trampoline) and not appear dizzy
-Be a thrill seeker or daredevil
-Need to move constantly
-Enjoy being upside down
-Enjoy swinging very high and for a long time
Some children may have difficulty detecting and discriminating vestibular input and may exhibit the following:
-Fall frequently or seat or while moving
-Become easily confused when turning or changing directions
-Be unable to tell when they have had enough swinging, possibly continuing until feeling sick
The proprioceptive system provides information about our bodies. More specifically it tells us about the position, force, direction and movement of our own body parts. It tells us what position our bodies are in and where our body is in the environment. It helps us learn to use skilled movement and feel comfortable as we move through the environment. The proprioceptive system has the largest receptor out of all the sensory systems. All the skeletal muscles in our body are receptors for our proprioceptive system. This system sends messages about whether the muscles stretch or contract, and how the joints bend and straighten. Even when we aren’t moving our proprioceptive system is responding against gravity. This system increases body awareness and contributes to motor control and motor planning. It helps us move our body efficiently, walk smoothly, run quickly, climb stairs, carry a back back, sit, and stand. It can help us feel emotional secure because when we are comfortable in our own skin and trust our bodies, we feel safe and secure. When you close your eyes how do you know where your feet are, your arms, your hands? Your proprioceptive system is the internal sense that gives you this information.
Children with inefficient proprioceptive processing may exhibit some of the following:
-Poor sense of body awareness, clumsy, frequently bump into people/things
-Be stiff, uncoordinated
-Falling and tripping frequently
-Lean, bump, or crash against objects and people
-Invade others personal space
-Have difficulty with new motor tasks
-Be unable to do familiar things without looking
-Use increased force on pencils or other small items to the point that they break
-Walk and run with heavy, hard feet
-Difficulty managing buttons, snaps, and zippers
-Hugs very tight and strong
-Discomfort with vision being blocked
-Frequently slumped at desk or avoiding movement all together
-Chew on clothing or objects frequently
Now that you know all about the vestibular and proprioceptive system, you are likely wondering what you can do to help your child develop optimally in these areas. Check back in with us in a few weeks for Part II to this post! Please post any comments, questions, and personal experiences with anything related to vestibular and proprioceptive sensory processing in the comments section below.
References:
Biel, L., & Peske, N. (2009). Raising a Sensory Smart Child: The Definitive Handbook for Helping Your Child with Sensory Processing Issues. New York, NY: Penguin Books.
Ganz, J.S. (2008). Sensory Integration Strategies for Parents: SI at Home and School. Prospect, CT: Biograhical Publishing Company.
Kranowitz, C. (2003). The Out of Sync Child Has Fun: Activities for Kids with Sensory Processing Disorder. New York, NY: Penguin Group.
